English_ivy_1We all know them: English ivy, European starlings, Himalayan blackberry, Scotch broom. No, they’re not foreign exchange students or international meals. They’re part of the legion of exotic invasive species that threaten the ecological integrity of the Northwest. Of course, the Northwest is hardly alone. The American south is overrun with kudzu, for instance.

The poster children of over-abundance are deer, as anyone in the Upper Midwest or the Northeast can tell you. Deer, of course, are native species, but because their predators have largely been eliminated, and because they thrive in semi-developed fragmented landscapes, they are legion. But deer are not alone: Canada geese, grackles, raccoons, opossums, and other species can wreak havoc on ecosystems that are already out of balance.

A good article today, picked up by the Seattle Times, examines the consequences of our alteration of ecosystems. Not only do some foreign invaders out-compete native species, but the populations of a few native species metastasize at the expense of more sensitive species. Here is the crux of the article:

…what’s happening isn’t natural. It’s all man’s fault. As the land is changed, often to accommodate development, ecosystems turn much more vanilla, scientists say.

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The world does better when it has a buffet of diverse species — some of those plants and animals can benefit people with food and medicine — instead of one flavor fits all, said Oregon State University zoology professor Jane Lubchenco, president of the International Council for Science.

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